This invention relates generally to sawing devices, and more particularly, is directed to a device for cutting railroad rails in place, in the field or in the shop.
Previously, the cutting of railroad rails has been accomplished by the method of oxy-fuel cutting, that is, through the use of acetylene, natural gas, or other fuel and oxygen mixtures. There are numerous disadvantages of oxy-fuel cutting of railroad rails, such as heat distortion of the rail, poor accuracy of the cut (due to inconsistent cut width), poor quality of the cut (due to irregular surface), inability to weld the rail (due to the quality of the cut), the necessity to clean up by grinding the end of the cut for preparation for the weld or for bolting onto another section of the rail.
Another known method of cutting a railroad rail is by means of abrasive cutting machines, that is, abrasive cut-off grinders utilizing silicon carbide cut-off wheels, driven by high horsepower motors. However, there are also numerous disadvantages of abrasive machining for the cutting of railroad rails. First and foremost is the high cost of cut-off wheels. Another disadvantage is the speed of rotation of such wheels at approximately 16,000 surface feet per minute, requiring extensive reinforcing of the cut-off wheel. Abrasive machining also develops considerable heat and thus, heat distortion of the rail occurs. Most railroad rails are of a high tensile alloy steel that is designed specifically to be abrasion resistant, and for this reason, has a tendency to glaze when abrasive machining is utilized, thus leading to the very rapid wear of grinding wheels. In both abrasive and oxy-fuel cutting methods, there are also inherent dangers to the operator.
In the 1980s, the use of welded railroad rails have become very pronounced, and it is anticipated that this process will grow in the coming years. In the future, all rails will be cut with cold machining as described with respect to the present invention.
An electrical carrier utilized by some urban transportation systems, such as Bart, San Francisco, and the like, is a new type of third rail system. This third rail system is a steel I-section which has aluminum fused to the web on both sides. This type of rail cannot be cut efficiently by either the oxy-fuel cutting method or the abrasive method because of the melting point variation between aluminum and steel. Cold saws can cut such composite material without difficulty.